(a) Field of the Invention
This invention relates to a light leakage preventing device in a reflex camera wherein, when a reflecting mirror is in a position in which it can conduct a light from an object to be photographed to a finder system, the light can be prevented from leaking from the upper edge and lower edge of the reflecting mirror to a film.
(b) Description of the Prior Art
In a conventional reflex camera, as no particular light intercepting device is provided on the bottom part of a mirror box formed within the camera body or the free end edge of a reflecting mirror rotatably provided within the mirror box, even when the reflecting mirror is in a position (that is, a down position) in which it can not conduct a light from an object to be photographed to a finder system, the entry of the light toward the film surface through between the free end edge, that is, the lower end edge of the reflecting mirror and the floor surface of the mirror box can not be avoided. Therefore, in a focal plane shutter device to be set between the rear part of the mirror box and the film, a means of intercepting the above mentioned entering light has had to be taken. That is to say, in case a blade type focal plane shutter formed, for example, by overlapping a plurality of laminas is used, the overlaps of the respective laminas will have to be made large to prevent the light leakage. This means that the areas of the respective laminas must be made larger. Therefore, the masses of the laminas will increase. If the respective laminas thus become larger and the masses increase, it will become hard to obtain a shutter device operating at a high speed and it will become impossible to meet the requirement of making the shutter device small.